Field of the Invention
The present invention relates generally to borehole reamers to enlarge the size of drilled borehole and, more particularly in some non-limiting embodiments, to a downhole intelligent reamer controller that can detect the difference between rotary drilling and sliding drilling, respond appropriately and quickly to multiple changes between rotary drilling and sliding drilling that may occur several times each stand of pipe, with additional controls to prevent deployment of reamer members at inappropriate times such as when drilling out cement, testing, and running in and out of the wellbore.
Background of the Invention
Expandable reamers or underreamers are well known in the oilfield drilling industry. The term reamer and underreamer is used herein interchangeably although often a reamer is considered to be a fixed blade device that may be the same or approximately the same size as the bit size.
It is often desirable to increase the annular space in a wellbore for various reasons. Typical reasons may be to provide additional annular space for cementing, increased production flow area, to allow for increased casing size, to clean the hole where swelling occurs, increase annular space to avoid surge pressures when running a liner, Equivalent Circulating Density (ECD) problems, swelling shales, creeping salts, sloughing/cave-ins, casing exits and the like.
An expandable reamer may typically have two basic operative states. In one state, the reamer member or members are closed or in a collapsed state where the diameter of the reamer tool is smaller, for example, sufficiently small to allow the tool to pass through existing open or cased borehole. In the second state, an open or partly expanded state is provided, where one or more reamer members with cutters on the end (cutter blocks) thereof extend from the body of the tool. In the expanded state, the reamer enlarges the borehole diameter as the tool is rotated and lowered and/or raised in the borehole. The reamer or underreamer typically operates during rotation of the drill string and is typically actuated by drilling fluid flow.
In some types of drilling operations, such as certain types of directional drilling operations, both rotating drilling and sliding drilling is utilized when the drive mechanism for the drill bit is either a Positive Displacement Mud Motor (Mud Motor), or a Downhole Turbine (Turbine). The mud motor and the turbine have similar components, which are the Power Section, Transmission Bent Housing Section and Bearing Stabilizer Section. The Power Section is comprised of a Rotor and Stator, whereby the rotor is turned by the pressure drop across either the cavities in the mud motor, or across the turbine stages in the turbine, which turns the bit. The Transmission Bent Housing Section contains couplings inside that eliminate all eccentric rotor motion and accommodate the misalignment of the bent housing, while transmitting torque and down thrust to the drive shaft. The Bearing Stabilizer Section contains the Bearing Assembly, comprised of multiple thrust-bearing cartridges, radial bearings, a flow restrictor, and a drive shaft. The housing of the Bearing Assembly can have a threaded O.D. to accommodate a thread on stabilizer sleeve. If no stabilization is required, a non-threaded version slick housing can be used. The drive shaft has standard drilling thread connections to connect the motor to the drill bit. For the sake of simplicity, the term for the drive mechanism used herein is a mud motor.
A mud motor is utilized during sliding drilling—when the drill string is substantially non-rotating and the bend is oriented in the desired direction to guide the trajectory of the borehole toward the target location.
As part of the rotating/sliding directional steering process with a mud motor, the drill string is often frequently changed between rotating drilling and sliding drilling. Sliding drilling creates an initial deviation arc, which is then followed by rotating drilling to provide directional control. For example, both sliding and rotating drilling may alternately be used several different times while drilling each stand of drill pipe, wherein a stand of drill pipe may comprise of two or more pipes connected together. Due to frequently alternating changes in types of drilling, prior art expandable reamers have significant disadvantages when used for rotating/sliding directional steering operations making them unsuitable, slow to open and close, and/or incapable for this purpose.
Many expandable reamers expand in response to pumping drilling fluid at a certain rate or pressure. However, due to the need for pumping drilling fluid during the sliding directional drilling, if the reamer expands due solely to drilling fluid flow this can be very problematic. In most cases, expandable reamers are designed to remain closed until a ball, dart, RFID Tag, or other object is dropped, or pumped, down the Internal Diameter (ID) of the drill string to initially expand the tool. For the sake of simplicity, the term for the object dropped herein is a ball. The time required for the ball to reach the reamer results in significant lost rig time, making this type of expandable reamer unsuitable for rotating/sliding drilling operations with mud motors. Even if this type of device can be repeatedly closed for sliding drilling, which is not normally the case, this type of activation is not well suited to switching quickly between sliding drilling and rotary drilling. Dropping balls to close the reamer for sliding drilling is not realistically practical due to extensive lost rig time.
Mechanical and/or Hydraulic systems that respond to variations to drilling fluid flow or pressure, whereby the nominal flow rate is reduced temporarily, can be utilized to expand or close the tool multiple times are available, without the need to drop a ball. However, the variations in fluid flow or pressure, which is required to expand or retract the reamer members are time consuming to operate when switching frequently between rotary drilling and sliding drilling. Reducing the flow rate may also adversely affect the performance of the drive system. In addition, repeated flow reductions will significantly increase time lost due to switching and may be prone to both personnel and mechanical operation errors with frequent switching.
Recent art utilizing electronic systems may require frequent down link commands. Down link commands can be described as manual alterations to the rig pump and/or rotary speed settings in a specific sequence. Down link commands can also be transmitted using a controlled valve that shunts a portion of the drilling fluid going to the standpipe, back to the active mud tank. Down linking transmits encoded instructions to the downhole electronics to either open or close the underreamer when switching frequently between rotary drilling and sliding drilling. Repeated downlinking; however, result in significant time lost in switching the reamer members between an expanded or retracted.
Examples of background patents and publications in the general area of expandable reamers include:
U.S. Publication NO 2013/0306,373 discloses an electronically activated tool comprising a tool body, cutter blocks and sensors with means for attachment to a drilling support and rotation so as to permit the simultaneous underreaming and measurement of the diameter of a wellbore (especially in oil and gas drilling) characterized by a means of activation using an electronic signal sent by mud-pulse, fiber-optics, wireless transmission or other means which may also communicate commands and receive data from the underreamer during drilling, at least one radially extendable cutter block incorporating positional sensors adapted to measure the relative position of the cutter block to the tool, at least one caliper means to measure wellbore diameter, all of which are inter-linked by a means of communication using receivers, sensors and microprocessors.
U.S. Publication No 20100282511 discloses a wired reamer for use on a downhole drill string. In some embodiments, the reamer includes a reamer body comprising a pathway therethrough and wiring located within the pathway for transmitting at least one of power or communications. In other embodiments, the reamer includes a reamer body comprising a pathway enclosed within the reamer body, wiring located within the pathway for transmitting at least one of power or communications, a sensor and a processor located within the reamer body. The sensor is connected with the wiring for transmitting data measured by the sensor through the wiring, and the processor is connected with the wiring for receiving the data from the sensor.
U.S. Pat. No. 8,235,144 discloses an expansion and sensing tool comprising a tool body, cutter blocks and sensors which permit simultaneous underreaming and measurement of the diameter of a wellbore drilled by an oil and gas rig. Radially extendable cutter blocks incorporating positional sensors contained on the block or within the body measure the position of the cutter block relative to the tool, and a vibration sensor measures vibration and underreaming wellbore dimensions in real-time. Receivers, sensors and microprocessors deliver a desired wellbore depth both simultaneously comparing and correlating measured vibration data and underreaming parameters. The tool may be optionally configured with a caliper or a stabilizer.
U.S. Publication No. 20110284233 discloses a downhole tool assembly configured for repeated and selective hydraulic actuation and deactivation. A piston assembly is configured to reciprocate axially in a downhole tool body. The piston assembly reciprocates between a first axial position and second and third axial positions that axially oppose the first position. The downhole tool is actuated when the piston assembly is in the third axial position and deactivated when the piston assembly is in either of the first or second axial positions. A spring member biases the piston assembly towards the first axial position while drilling fluid pressure in the tool body urges the piston assembly towards the second and third axial positions. Downhole tool actuation and deactivation may be controlled from the surface, for example, via cycling the drilling fluid flow rate.
U.S. Pat. No. 5,060,736 discloses a bottom hole assembly having a bit driven by a downhole motor and stabilizers located above the motor on the drill string. A subassembly is also provided for controlling the bit trajectory that is operational on demand at the rig site. The subassembly comprises an underreamer located directly above the bit. The underreamer is hydraulically actuated to retract and extend the cutters.
U.S. Pat. Nos. 7,506,703 and 7,597,158 disclose an expandable drilling apparatus deployed upon a distal end of a drillstring and includes a cutting head and a substantially tubular main body adjacent the cutting head providing a plurality of axial recesses configured to receive arm assemblies configured to translate between a retracted and an extended position. A flow switch actuates the arm assemblies when a drilling fluid pressure exceeds an activation value and the drilling apparatus includes a biasing member to reset the arm assemblies when the drilling fluid pressure falls below a reset value.
U.S. Pat. No. 5,746,278 discloses an apparatus and method for controlling an underground boring machine during boring or reaming operations. A boring tool is displaced along an underground path while being rotated at a selected rate of rotation. In response to variations in underground conditions impacting boring tool progress along the underground path, a control system concurrently modifies the rate of boring tool displacement along the underground path while rotating the boring tool at the selected rotation rate. The controller monitors the rate at which liquid is pumped through the borehole and automatically adjusts the rate of displacement and/or the liquid flow rate so that sufficient liquid is flowing through the borehole to remove the cuttings and debris generated by the boring tool. Sensors are provided to sense pressure levels in the rotation, displacement, and liquid dispensing pumps and an electronic controller continuously monitors the levels detected by the sensors. When the controller detects a rise in rotation pump pressure above an unacceptable level, the controller disengages the boring tool by reducing the rate of boring tool displacement along the underground path, while maintaining rotation of the boring tool at a pre-selected rate. Such disengagement reduces the load on the rotation pump and allows the pressures to recover to an acceptable level. The controller re-engages the boring tool after detecting that the rotation pump pressure has fallen below a set level.
U.S. Pat. No. 7,823,663 discloses a downhole apparatus that comprises a body, extendable members mounted on the body and being movable between retracted and extended configurations, and a remotely operable retaining arrangement for maintaining the extendable members in the retracted configuration. The extendable members may be cutters, such that the apparatus may be a cutting apparatus, such as a reamer. An operator may control the apparatus to retain the cutting members in the retracted configuration, or prevent the extension of the cutting members.
U.S. Pat. No. 8,215,418 discloses an expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.
U.S. Pat. No. 6,470,977 discloses a steerable bottom hole assembly used for drilling both a curved section and straight section of the borehole, with the bottom hole assembly including a reamer beneath the downhole motor. The bottom hole assembly includes a bit having a bit face defining a bit diameter, and a gauge section having a substantially uniform diameter cylindrical surface approximating the bit diameter and having an axially length of at least 75% of the bit diameter. The motor is preferably run slick without stabilizers for engaging the wall of the borehole.
U.S. Pat. No. 6,732,817 discloses a downhole tool that functions as an underreamer, or alternatively, as a stabilizer in an underreamed borehole. The tool includes one or more moveable arms disposed within a body having a flow bore therethrough in fluid communication with the wellbore annulus. The tool alternates between collapsed and expanded positions in response to differential fluid pressure between the flow bore and the wellbore annulus. In one embodiment, the tool moves automatically in response to differential pressure. In a second embodiment, the tool must be selectively actuated before it is moveable. When the tool expands, the arms are preferably translated axially upwardly, while simultaneously being extended radially outwardly from the body. The expanded tool diameter is adjustable at the surface without changing components. The arms may include borehole engaging pads that comprise cutting structures or wear structures or both, depending upon the function of the tool.
U.S. Publication 20040188142 discloses a horizontal directional drilling system used to drive operation of a guidable reamer assembly connected to a drill string. The guidable reamer assembly preferably has a cutting member with a central longitudinal axis and a support member also having a central longitudinal axis. The longitudinal axes of the cutting member and the support member are collinear when the reamer assembly is in the non-steering position and laterally displaced when in the steering position.
U.S. Pat. No. 4,848,490 discloses a directional downhole stabilizer for use in a drill string. The stabilizer has an effective diameter which is selectively variable between a minimum diameter and a maximum diameter depending on the load on the drill string. The effective diameter is determined by radially movable spacers which are caused to move radially on relative movement of a mandrel which telescopes within the stabilizer casing and which has cam surfaces which engage the radial spacers. The telescopic movement of the mandrel within the casing is controlled via a mechanical detect arrangement which is actuated by the compressive force on the stabilizer.
U.S. Pat. No. 7,757,787 discloses an expandable drilling apparatus that includes a main body comprising a central bore and at least one axial recess configured to receive an arm assembly operable between a retracted position and an extended position, a biasing member to urge the arm assembly into the retracted position, a drive position configured to thrust the arm assembly into the extended position when in communication with drilling fluids in the central bore, a selector piston translatable between an open position and a closed position, wherein the selector piston is thrust into the open position when a pressure of the drilling fluids exceeds an activation value, wherein the drilling fluids are in communication with the drive piston when the selector piston is in the open position, and a selector spring configured to thrust the selector piston into the closed position when the pressure of the drilling fluids falls below a reset value.
U.S. Publication 20060113113 discloses a bottomhole assembly that includes a drill bit, a stabilized underreamer assembly located behind the drill bit, and a drilling assembly. A method to drill a formation includes positioning a stabilized underreamer assembly behind a drill bit, positioning a drilling assembly behind the stabilized underreamer assembly, and rotating the drill bit and stabilized underreamer assembly with the drilling assembly. A stabilized underreamer located between a directional drilling assembly and a drill bit includes at least one arm assembly extending from the stabilized underreamer assembly, wherein the arm assembly includes a stabilizer portion and an underreamer cutting structure.
U.S. Publication No 20070163810 discloses a bottom hole assembly to directionally drill a subterranean formation includes a drill bit, a stabilizer assembly located proximate to and behind the drill bit, a drilling assembly comprising a drive mechanism and a directional mechanism, and a flex member. Optionally, the flex member may be located between the drilling assembly and the stabilizer assembly or an integral to a housing of the drilling assembly. A method to drill a formation includes positioning a stabilizer assembly behind a drill bit and positioning a flex member between an output shaft of a drilling assembly and the stabilizer assembly. The method preferably includes rotating the drill bit, stabilizer assembly, and flex member with a drilling assembly and directing the trajectory of the drill bit and stabilizer assembly with a directional mechanism of the drilling assembly.
U.S. Publication No 20100139981 discloses A bottomhole assembly (BHA) coupled to a drill string includes one or more controllers, and a hole enlargement device that selectively enlarges the diameter of the wellbore formed by the drill bit. The hole enlargement device includes an actuation unit that may move extendable cutting elements of the hole enlargement device between a radially extended position and a radially retracted position. The actuation unit may be responsive to a signal that is transmitted from a downhole and/or a surface location. The hole enlargement device may also include one or more position sensors that transmit a position signal indicative of a radial position of the cutting elements. In an illustrative operating mode, one or more operating parameters of the hole enlargement device may be adjusted based on one or more measured parameters. This adjustment may be done in a closed-loop or automated fashion and/or by human personnel.
The above publications and patents are hereby incorporated herein by reference.
Accordingly, there exists a need for an intelligent downhole controller, which addresses the problems described hereinbefore. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems.